Derivation and validation of a novel functional FFR CT score incorporating the burden of coronary stenosis severity and flow impairment to predict clinical events.

Background: A score combining the burden of stenosis severity on coronary computed tomography angiography (CCTA) and flow impairment by fractional flow reserve derived from computed tomography (FFR _CT ) may be a better predictor of clinical events than either parameter alone.
Methods: The Functional FFR _CT Score (FFS) combines CCTA and FFR _CT parameters in an allocated point-based system. The feasibility of the FFS was assessed in cohort of 72 stable chest pain patients with matched CCTA and FFR _CT datasets. Validation was performed using 2 cohorts: (a) 4468 patients from the ADVANCE Registry to define its association with revascularization and major adverse cardiovascular events (MACE); (b) 212 patients from the FORECAST trial to determine predictors of MACE.
Results: The median calculation time for the FFS was 10 (interquartile range 6-17) seconds, with strong intra-operator and inter-operator agreement (Cohen's Kappa 0.89 (±0.37, p ​< ​0.001) and 0.83 (±0.04, p ​< ​0.001, respectively). The FFS correlated strongly with both the CT-SYNTAX and the Functional CT-SYNTAX scores (rS ​= ​0.808 for both, p ​< ​0.001). In the ADVANCE cohort the FFS had good discriminatory abilities for revascularization with an area under the curve of 0.82, 95 ​% confidence interval (CI) 0.81-0.84, p ​< ​0.001. Patients in the highest FFS tertile had significantly higher rates of revascularization (61 ​% vs 5 ​%, p ​< ​0.001) and MACE (1.9 ​% vs 0.5 ​%, p ​= ​0.001) compared with the lowest FFS tertile. In the FORECAST cohort the FFS was an independent predictor of MACE at 9-month follow-up (hazard ratio 1.04, 95 ​% CI 1.01-1.08, p ​< ​0.01).
Conclusion: The FFS is a quick-to-calculate and reproducible score, associated with revascularization and MACE in two distinct populations of stable symptomatic patients.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)